In recent years, as portable terminals such as cellular phones, ones having various structures such as a foldable (rotatable) structure and a slidable structure have been put into practical use. In the case of connecting components (circuit hoards) that can carry out rotation, linear movement, and so on to each other by a signal line, the components are electrically connected to each other e.g. by using a flexible cable and a harness and sliding the contact point.
For example, a portable terminal having an upper case and a lower case freely slidably coupled with each other is disclosed in Japanese Patent Laid-open No. 2006-303719 (Page 4, FIG. 1) (hereinafter, Patent Document 1). In the slidable portable terminal, the circuit board in the upper case and the circuit board in the lower case are electrically connected to each other by the flexible substrate. Furthermore, a communication device having an interface unit rotatably coupled with a casing via a hinge mechanism is disclosed in Japanese Patent Laid-open No. 2007-534242 (Page 7, FIG. 4) (hereinafter, Patent Document 2). In the rotatable communication device, the interface unit and the electronic circuit in the casing are electrically connected to each other by the electric cable provided in the arm.
In addition, a method of using optical communication has also been proposed as a method for data transmission. For example, an optical connector that includes a convex holder having a laser diode and a concave holder having a photodiode is disclosed in Japanese Patent Laid-open No. 2005-333019 (Page 6, FIG. 1) (hereinafter, Patent Document 3), In this optical connector, the concave holder is engaged with the convex holder, which allows optical communication.
However, these Patent Documents include the following problems.
(1) For the portable terminals disclosed in Patent Documents 1 and 2, the cable needs to be folded, twisted, and expanded/contracted in the rotation and sliding of the case, which causes a problem that a heavy load is applied to the bent part and the twisted part and therefore the endurance is lowered. In recent years, along with increase in the information transmission amount and enhancement in the transmission speed, increase in the number of signal lines, increase in the cable width and the diameter of a bundle of cables, reduction in the size per one cable, and so on are being advanced. Therefore, it is expected that the lowering of the endurance will lead to large problems.
(2) The method of sliding the contact point in the slidable portable terminal involves a problem that change in the mechanical load and electric signal noise occur due to change in the contact pressure.
(3) For the optical connector disclosed in Patent Document 3, operational restrictions are caused because communication is carried out with the convex holder engaged with the concave holder. Therefore, for example, it is difficult to carry out data transmission in the state in which a case like the above-described ones is rotated and slid.
There is a need to provide an electronic apparatus that is free from operational restrictions and has enhanced endurance and reliability.